1. Field of the Disclosure
This disclosure relates generally to blowout preventers used in hydrocarbon drilling and production operations. In particular, the disclosure relates to systems and methods to facilitate assembly, disassembly and on-site maintenance of a piston rod subassembly of a blowout preventer.
2. Description of Related Art
In hydrocarbon drilling and production operations, blowout preventers can be used to block the flow of fluids through a wellbore by having rams that close across the wellbore. The rams can either seal an empty wellbore, or seal the wellbore around a drillpipe, polished rod, or other tools or equipment that is within the wellbore. The ram may alternately be a shear ram, which, when activated, moves to engage and physically shear any member in the wellbore. The rams can alternately be gripping rams that can engage the tubular, polished rod, or other equipment in the well to prevent axial or rotational movement of such tubular, polished rod, or other equipment in the well.
The piston rod subassembly of some current blowout preventers can be a single member with both a piston rod and tail rod that are fully formed of expensive alloys to achieve the desired strength of the piston rod, as the rams and piston rods can be subjected to significant forces and an extreme environment during operation of the blowout preventer.
In some current systems where the piston rod assembly is formed of multiple members, the connection between the members can be preloaded so that the members do not work loose during operation of the blowout preventer. However, the preload on the connection between the members of such current systems requires that the components be sent off-site in order to separate the members for repair, replacement, or salvage.